There have been a number of proposed non-azide gas generant compositions.
Among those is a composition based on a very restricted number of metallic salts of 5-nitrobarbituric acid and an equally restricted number of metal-cation containing oxidizers which is described in U.S. Pat. No. 5,015,309, the disclosure of which is incorporated herein by reference. According to the known proposal, a non-azide gas generant is composed of about 25 to 75% by weight of anhydrous metal salts of 5-nitrobarbituric acid wherein the metal is selected from metals of Group I-A of the Periodic Table of Elements (except sodium), calcium, strontium, or barium, and about 75 to 25% by weight of an anhydrous oxidizing salt having a metal cation selected from the group consisting of metals of Group I-A of the Periodic Table of Elements (except sodium), calcium, strontium, or barium, plus from 0 to 5% by weight of a binder. Although these gas generant compositions have received some interest, the compositions suffer from various drawbacks. Of the most promising compositions is one containing the potassium salt of 5-nitrobarbituric acid. However, compositions based on the potassium salt exhibit several severely limiting drawbacks such as high particulate levels and very high carbon dioxide levels. Solids from the combustion of the preferred potassium salt include potassium hydroxide and potassium oxide which are highly caustic materials.
The potassium oxide and potassium hydroxide solids present problems similar to those created by the sodium oxide and sodium hydroxide combustion products from sodium azide based gas generant compositions. For instance, sodium azide-based gas generants have combustion products that can be toxic because molybdenum disulfide and sulfur are presently the preferred oxidizers for use with sodium azide. The reaction of these materials with sodiumazide produces toxic hydrogen sulfide gas, corrosive sodium oxide, sodium sulfide, and sodium hydroxide powder. Rescue workers and automobile occupants have complained about both the hydrogen sulfide gas and the corrosive powder, e.g., sodium hydroxide, produced by the operation of sodium azide-based gas generants. Like problems are to be expected with the potassium by-products from a non-azide gas generant based on the potassium salt of 5-nitrobarbituric acid.
It would, therefore, be a significant advance in the art to provide a non-azide fueled gas generant composition which does not suffer from the defects associated with the presently proposed sodium azide fueled gas generants and the aforementioned composition composed of a restricted class of metallic salts of 5-nitrobarbituric acid and a restricted class of oxidizers.
Such compositions are disclosed and claimed herein.